Mechanism Of Flaxseed Gum Fermentation By Gut Microbiota Affecting Energy Metabolism

Obesity and its related metabolic disorders have been a global pandemic.We found that flaxseed gum had an anti-obesity effect through promoting lipid metabolism,inducing satiety and regulating gut microbiota.Whether the slimming effect of flaxseed gum is mainly realized by the metabolites produced by intestinal microbiota fermentation of flaxseed gum remains to be further studied.First,the degradation of flaxseed gum by gut microbiota was studied;then,the effects of metabolites of fecal bacteria fermentation liquid on energy metabolism and fat production were discussed;finally,the differentially expressed genes of colonic epithelium between the FG-diet group and obese group were further studied,and the pathways related to energy metabolism and lipid metabolism were analyzed.The results are as follows:1)The fermentation broth containing linseed polysaccharide could be degraded by fecal flora of rats fed with linseed gum,but the degradation degree decreased after subculture.The relative abundance of Lachnospiraceae?NK4A136?group and 48 metabolites in rat feces increased with the intervention of linseed polysaccharide,but decreased in vitro.2)The metabolites significantly inhibited glucose intake through downregulating the m RNA and protein expression of GLUT2 and SGLT1 in Caco-2 cells.Besides,they also led to the decrease of lipid accumulation through downregulating the m RNA and protein expression of PPAR?,C/EBP?,and C/EBP? in 3T3-L1 cells.The inhibitory effects on energy intake and adipogenesis were concentration dependent,and metabolites at physiological concentration showed the most significant effect.3)Based on KEGG analysis of genes in colonic epithelium,we found three classical pathways related to lipid metabolism and energy metabolism,including PPAR signaling pathway,nitrogen metabolism and oxidative phosphorylation.Flaxseed gum intervention regulated gene expression related to fatty acid catabolism and inflammation through PPAR signaling pathway,and regulated gene expression related to fatty acid oxidation products transforming to ATP through nitrogen metabolism and oxidative phosphorylation pathway.In addition,the results of q PCR confirmed the accuracy of RNA-Seq analysisIn short,flaxseed gum may be degraded by Lachnospiraceae?NK4A136?group and other key bacteria,which might take the compounds such as docosahexaenoic acid and 2-dimethylaminoindole(gramineine)as the growth factors of bacteria;The inhibitory effects on energy intake and adipogenesis were concentration dependent,and metabolites at physiological concentration showed the most significant effect;The metabolites of flaxseed gum acted on intestinal epithelial tissues and affected lipid metabolism and energy metabolism by regulating the expression of PPAR signaling pathway,nitrogen metabolism and oxidative phosphorylation pathway related genes.